1. Field of the Invention
This invention relates to an inner diameter measuring machine wherein measuring elements supported by a measuring element supporting portion of a main body of the measuring machine are linearly moved by means for operating a lever a nd the like in a direction perpendicularly intersecting an axial direction of the main body of the measuring machine to be brought into contact with the inner surface of a hole of an article to be measured, and a movement value of the measuring elements at this time is detected by an encoder to be displayed in a display device.
2. Description of the Related Art
As the inner diameter measuring machine, there has heretofore been known one wherein a displacement value of a spindle is detected by a dial gauge to thereby measure an inner diameter of a hole of an article to be measured. In recent years, there is such a background that, in order to realize high precision measurement, prevention of reading errors, measurement of high added value by adding various functions and the like, an electronic display type inner diameter measuring machine is demanded. Therefore, similarly to other measuring machines, it is conceivable that the inner diameter measuring machine should adopt the electronic display type one too.
Now, since the conventional inner diameter measuring machine adopts a dial gauge as means for displaying a movement value of the spindle, such a construction should necessarily be used that has the dial gauge provided at one end of a body case containing therein the spindle, and operating means provided in the intermediate portion of the case body. Accordingly, even if the operating means is formed of a pair of levers symmetrically arranged, an appropriate position is difficult to be held, thus rendering the mechanism large-sized and complicated. Since one end of the case body becomes heavy, handling is hard and operation is possible only in the vertical position of the case body. Further, a measured value should be visually read while the measuring element is in contact with the inner surface to be measured, whereby the measurable range of a subject to be measured is restricted greatly, thus narrowing the applicability.
On the other hand, in this arrangement, even if the dial gauge is replaced by an electronic type displacement detecting means, when thermal expansion, deformation and the like of the long spindle are taken into consideration, it is difficult to achieve the proper measuring accuracy thereby rendering the results substantially meaningless. The hard handling and restricted measuring position are still unimproved.
As described above, with the inner diameter measuring machine, it has been difficult to make achievement of a desirable measuring accuracy compatible with enlarged applicable range of the article.
An object of the present invention is to provide an inner diameter measuring machine excellent in controllability and handling properties.
Another object of the present invention is to provide an inner diameter measuring machine wherein the measuring accuracy intrinsic to an electronic type displacement detector is not lowered.